Process of separating waxes



NGV. 17, 1942. E MTDONS r 2,302,434.

PROCESS OF SEPARATING WAXES Filed Dec. :26, 1941 HIGH MELTING POINT WAX HEATER 3 OR 20 COOLER SOLVENT Aaou'r,

so F. To 80 E 2| l9 CLEANSING zoNE/ IDISSOLVING ZONE g Q PREUMINARY CLEANSING ZONE f f WAX BREAKER l WAXES I SETTLING CHAMBER i a INCOMING SOLUTION OF. TO 20F". OlL,LOW MELTING POINT WAX AND HIGH MEI-TING POINT WAX COOLEV 5 Q5 1 8) ABOUT VWW I 7 DISSOLVED m SOLVENT H soufmimr LOW MELT m; POINT WAX AND'ISOLVENT INVENTORSI E. M. DONS l2 By 0. c. MAURO WFQ E rvvmzt DEWAXED OIL AND SOLVENT ATTORNEYS.

Patented Nov. 17, 1942 PROCESS OF SEPARATING WAXES Eddie M. Dons and Oswald G. Mauro, Tulsa, Okla., assignors to Mid-Continent Petroleum Corporation, Tulsa, Okla., a. corporation of Delaware Application December 26, 1941, Serial No. 424,400

11 Claims.

This invention relates to processes of separating waxes having diiferent melting points, The novel conditions may be employed to separate slack wax, or petrolatum, into high melting point wax, low melting point wax, and oil. However, the wax separating conditions can be utilized to separate various other kinds of high and low melting point Waxes either with, or without, a recovery of oil as a separate product. Inthe preferred form of the invention, the valuable high melting point wax is preferably isolated from the low melting point waxes, and subjected to a refining or purifying operation which positively removes contaminating low melting point fractions from solidified particles of the high melting point wax.

An object of the invention is to produce a commercially feasible system which eliminates cumbersome and expensive operations heretofore involved in processes of this kind. A further object is to produce a very simple unitary continu ous process consisting of a novel combination of conditions which cooperate with each other to effectively accomplish the results of more expensive separate processes heretofore employed in the successive steps of separating and refining waxes.

More specifically stated, an object is to produce a simple counterflow extraction system wherein a relatively Warm solvent flows through a mixture of high and low melting point wax particles, so as to selectively dissolve the low melting point waxes without dissolving the high melting point waxes. A very desirable form of the invent-ion includes the steps of deflecting the solvent and wax particles into intersecting paths in a relatively warm dissolving zone to effectively dissolve low melting point waxes in the solvent stream, and thereafter deflecting the high melting point wax particles across the paths of warmer solvent in a cleaning zone, so as to forcibly scrub dissolved low melting point wax from surfaces of the deflected high melting point wax particles. I

Another cooperative detail of the new process includes the step of forcibly disintegrating the solidified mixture of waxes to release trapped liquid solution from the solidified wax, at the same time providing for highly efficient selection of low melting point fractions in the dissolving zone, and similar efliciency in the cleansing zone where dissolved low melting point waxes are scrubbed from the high melting point wax particles.

With the foregoingand other objects in view,

the invention" comprises the novel combination 55 and arrangement of cooperative details hereinafter specifically described to illustrate one form of the invention. However, it is to be understood that the scope of this patent extends to modifications and variations described by terms employed in the claims hereunto appended.

Fig. l is a diagrammatical view of a wax-separating system embodying features of this invention.

Fig. 2 is a fragmentary vertical section showing a wax-breaker, or disintegrator, in the course of waxes passing from a settling zone to a counterflow extraction system,

In separating slack wax, petroleum and other stocks containing high melting point waxes, low

melting point waxes and oil, the charging stock is preferably dissolved in a suitable selective solvent and then cooled to solidify the waxes in the liquid solution. For example, the stock known as slack wax, consisting of high and low melting point waxes and oil, may be dissolved in a relatively heavy solvent, and a continuous stream of the resultant solution may me admitted through the intake pipe 3, said intake being provided with a pump 4 and a valve 5 to regulate the continuous incoming stream.

This incoming stream flows through a chiller, or cooler, 6 where the flowing solution is cooled to a temperature desired for precipitation of waxes therein. The drawing indicates that this temperature may range between 0 F. and 20 F., and other temperature conditions are shown at various points in Fig. 1. However, these specific temperatures are merely for convenience in illustrating the importance of variations in the temperature conditions at different zones, and it is to be understood that the selected temperatures will depend upon the nature of the charging stock, the solvents, and the conditions desired in the different zones. The invention is not limited to the illustrative temperatures herein mentioned.

However, the temperature at the cooler 6 is low enough to precipitate or solidify the waxes in the liquid solution. This operation occludes, or traps, some of the oil solution in clusters of the wax crystals. One of our objects is to separate oil from the waxes. Therefore the mixture of oil solution and solidified waxes is preferably transmitted from the cooler 6 to a breaker, or disintegrator l, where the wax is forcibly broken into minute particles in the cooled oil solution. The trapped oil solution is thus liberated from the wax, and the mixture of oil solution and see annular settling chamber H around said inner chamber. In this form of the invention, the settling compartments 9 and H provide-a pair of settling zones immediatelybelow and in free communication with a counterfiow system hereafter described.

The incoming stream of chilled solution and free wax particles may be delivered from the pipe 8 to the settling chamber 9 at approximately the temperature selected for precipitation of wax 'in' the cooler, or chiller, 6, and we prefer to insulate the outer column l9, so as tomaintain predetermined extracting and cleansing temperatures therein.

We are now assuming that a relatively dense or heavy solvent has been'selected for this operation, and that the viscosity and interfacial tension are low enough to allow the wax particles to freely rise in the heavy solution. In this event, the major portion of the heavy solution will freely move downwardly by gravity to the bottom of the settling chamber 9 where it is discharged through a pipe 12. This outgoing solution is free of wax and it may be distilled in any suitable manner to remove the solvent from the dewaxed oil. It will be observed that most of the oil is very easily, quickly and economically dewaxed in the simple settling chamber 9, and immediately discharged from the dewaxing system. A low pour point oil is thus recovered as a separate product from the waxy mixture, and in a typical slack wax, this valuable oil may be about per cent of the original waxy mixture.

Attention is now directed to the setting zone established near this point where the incoming mixture of solvent and wax from pipe 8 enters the settling chamber 9. The mass of high and low melting point wax particles moves upwardly and carries with it minor portions of the solution, including oily films around the wax particles and relatively free portions of the solution between the rising wax particles. However, this rising mass moves through the open top of the settling chamber 9 and passes through a relatively heavy descending stream which may be produced by continuously introducing a stream of solvent through a pipe [3 leading into the upper portion of the column It].

In this form of the invention, the stream of cleansing solvent will freely descend in direct contact with the rising stream of wax particles, so as to dissolve the free portions of solution carried by the wax, and also forcibly scrub liquid films from the rising wax particles. If the temperature is high enough, the solvent will also melt and dissolve the low melting point wax fractions. These functions may be aided by any suitable mechanical appliances. For example, the counterfiow system may be provided with alternating baffles including a series of rings [4 extending inwardly from the inner face of the column Ill and a series of central baffle members l5 arranged as shown in the drawing to produce an elongated tortuous passageway wherein the rising wax particles move back and forth in a zigzag course. The stream of solvent descends through the rising stream of wax particles, and the counterflowing streams are divided into numerous layers of diiferent specific gravities contacting with each other and advancing in intersecting paths as they flow from one baffle to another. These bailles are preferably provided with upwardly inclined bottom faces to, permit free upward movement of the rising wax particles. It will be observed that the rising layers of wax particles move upwardly while in contact with the upwardly inclined bottom faces, and that said layers of wax particles intersect the descending solvent while rising from one upwardly inclined plane to another.

This feature tends to prevent the wax particles from clinging to the baiiles. However, any suitable mechanical means may be employed to pre vent or limit the growing of wax crystals which might otherwise extend from the bottom faces of the baffles. For example, the central bafiles [5 may be fixed to a rotary shaft 16, so as to rotate with the shaft at a very low speed, and scrapers I! may extend from the top faces of these rotary bafiles to remove waxy material from the bottoms of the stationary baflle ring l4. These stationary baffles 14 may be likewise provided with scrapers [8 extending from their top faces to remove waxy material from the bottom faces of the slowly rotating baffles. In' each case, the scrapers extend from the top of one bafile to a point adjacent to the bottom of the next higher baflle. It is not necessary to forcibly scrape the baffles, the object being to limit'the thickness of any wax deposit. tending to grow on the baflles, thereby eliminating obstructions that would tend to prevent free continuous flow of the wax and solvent.

Attention is now directed to certain conditions of the solvent stream introducted through the pipe I3. This pipe is equipped with a pump I9 and a valve 20 to deliver a continuous regulated stream of the solvent, and a variable heater or cooler 2| to regulate the temperature of the solvent stream. For example, in separating slack waxes, this solvent stream may enter the top of the counterfiow system at a selected temperature ranging between about 60 C. to about F., while the waxy mixture enters the settling chamber 9 at a selected temperature between about 0 F. and 20 F. Therefore, the temperature of the descending solvent stream is gradually decreased as it transfers heat to the rising wax particles.

Without attempting to point out the exact temperature at any given point in the counterflow system, we will state that the solvent stream from pipe I3 is warm enough to dissolve the low melting point waxes without dissolving the high melting point wax. The solvent stream descends through a series of different temperature zones and performs successive functions in the several zones, as will be presently described. The resultant descending solution is diverted from the top of the settling chamber 9 to the surrounding chamber l I, from Which it is discharged through a pipe 22. This deflection of the descending solution is due partly to the upward force of the rising stream of wax particles issuing from the top of the settling chamber 9, and partly to the free path for the descending current in the chamber II. The lowermost central bafile l5 also tends to deflect the descending stream toward the outer chamber I I. Some of the wax parti-.

cles may be swept into the outer settling chamber I I, but these wax particles are so light that they will eventually rise in the heavy solvent and return to the mass of wax, instead of passing to the bottom of said chamber l I.

V The wax particles from the top of the settling chamber 9 enter into the loWer portion of the counterflow system, and carry with them a minor portion of the oil solution in the form of oily films around the wax particles and some free solution between said particles. The incoming mass is subjected to a preliminary warming and cleansing operation in the lower portion of the counterfiow system, where the rising waxy material is repeatedly deflected into and across the paths of the relatively warm solvent, thereby producing intimate. forcible contacts between the solvent.

and wax particles, so as to dissolve the only material in the outgoing solvent. Therefore, the lower portion of the counterfiow system may be termed a preliminary cleansing zone, wherein oily material is removed from the wax particles to the counterfiowing solvent.

As the wax particles rise in the counterfiow system they enter into a warmer dissolving zone where the temperature of the descending solvent is high enough to melt and selectively dissolve the low melting point Wax fractions, without dissolving the high melting point particles.

Thereafter, the high melting point wax particles rise through a still warmer cleansing zone where the fresh incoming solvent scrubs minor portions of dissolved low m'eltin point waxes from the high melting point wax particles.

The forcibly cleansed high melting point wax particles then pass through a final cleansing zone to a wax outlet 29 above the counteriiow system, where an impeller 2d on the slowly rotating shaft i5 directs the outgoing wax toward said outlet 23. This final cleansing zone contains a body of fresh solvent which will tend to dissolve and remove any of the heavy solution that may be carried by the light wax particles.

The sequence of cooperative operations herein disclosed include the following:

Disinteorating the war erated in the disintegrator 1, which breaks the waxes into fine solid particles.

The settling operation The simple settling operation in chamber 9 causes the dissolved oil to separate from the high and low melting point wax particles. This desirable quiescent settling is not disturbed by the descending solvent stream in the counterfiow system. Since the descending solvent stream is diverted into the outer settling chamber l I, it does contaminate the outgoing dewaxed solution in pipe i2, and it permits free return of Wax particles that may be carried into said settling chamber H. The product of the simple settling in chamber 9 is a valuable dewaxed oil having a low pour point.

The preliminary cleansing zone A minor portion of the oil solution will be carried with the wax particles passing from the settling chamber 9 to the counterflow extracting system. This oil solution is immediately subjected to, the forcible cleansing and dissolving,

action of the relatively warm solvent stream descending through the lower portion of the counterflow system, so as to subject the wax particles to a cleansing action before they reach the dissolving zone.

The dissolving zone The cooperative conditions in the dissolving zone include the temperature high enough to selectively dissolve the low melting point wax frac tions, without dissolving the high melting point wax particles, and the manner in which the pre-' viously disintegrated wax is exposed to the relatively warm solvent. This operation includes the steps of spreading the stream of wax particles in said dissolving zone to separate and distribute the high and low melting point wax particles in the counterflowing solvent stream, while repeatedly deflecting the distributed wax particles and solvent stream into intersecting paths, so as to quickly and positively dissolve the selected low melting point waxes in the warmer solvent.

The warmer cleansing zone The undissolved high melting point wax particles are subjected to refining or purifying operations in the still warmer cleansing zone at the upper portion of the counterfiow system, where we spread the stream of wax particles to.

ing point wax is discharged through the outlet,

23, while a stream of the dissolved low melting point wax is discharged through the pipe 22-, the dewaxed oil being discharged through the pipe [2.

It will be observed that the step of breaking the wax is a desirable cooperative detail having an effect at each of the successive stages, beginning at the settling chamber 9 where the free oil solution is separated from the broken wax particles, and continuing through the successive zones in the counterflow system, where the disintegrated wax particles are most eifectively subjected to the selective dissolving and cleansing operations.

Fig. 2 illustrates a wax breaker, or disintegrator, 1 located in the-course of the deoiled wax particles passing from the settling chamber 9 to the counterfiow system. In Fig. 2, the upper portion of the chamber 9 is closed and provided with a wax outlet 25 leading to the disintegrator I, the latter having an outlet 26 through which the disintegrated wax particles are discharged into the counterflow system. A rotary impeller 21 in Fig. 2 will tend to deflect the wax into the outlet 25.

In actual practice we have found that the wax particles tend to coalesce in a settling zone, and that a wax-breaker arranged near thev entrance of the counterflow system will have the advantage of forcibly disintegrating the masses of wax for most effective distribution, scrubbingand selective dissolving in the counterfiow system.

It is to be understood the relatively broad aspects of the invention are not limited to details of the specific arrangement of chambers and zones herein disclosed, and that any suitable light or heavy solvents may be employed to produce the counterflow of wax and solvent. However, as an illustration of heavy solvent compositions selected for this invention, we will state that various compositions including methylene dichloride are desirable. More specifically stated, in separating slack wax, such compositions -may consist of '75 per cent methylene dichloride and 25 per cent dichlorethyl ether; or 75 per cent methylene dichloride and 25 per cent sulfur dioxide.

Examples of other heavy solvent compositions include dichlorodifiuoromethane and sulfur di oxide; perchlorethylene and sulfur dioxide; perchlorethylene and dichlorethyl ether.

We claim:

1. In the art of separating waxy materials having different melting points, a counterfiow' extraction process which comprises dissolving relatively low melting point waxes in a comparatively warm dissolving zone and separating dissolved low melting point wax from solidified Wax in a still warmer cleansing zone, said process including the steps of transmitting a stream of relatively warm solvent into said cleansing zone, causing the solvent stream to advance through said cleansing zone and then through said dissolving zone, cooling a liquid solution of said waxy materials to solidify waxes having different melting points, transmitting the cooled wax particles into said warm dissolving zone, causing a stream of the Wax particles to advance through said dissolving zone and then through said cleansing zone in contact with but in counterfiow relation to said solvent stream, regulating the temperatures to maintain the solvent stream in said dissolving zone at temperatures high enough to selectively dissolve wax fractions having relatively low melting points without dissolving the comparatively high melting point waxes, spreading the counterfiowing streams of solvent and wax particles into layers of different specific gravities contacting with each other at different elevations in said dissolving and cleansing zones, while repeatedly deflecting the counterflowing layers of wax particles and solvent into intersecting paths in said dissolving and cleansing zones, so as to' dissolve low melting point waxes in the solvent stream and thereafter scrub dissolved low melting point wax from surfaces of the deflected high melting point wax particles in the warmer cleansing zone, discharging dissolved low melting point waxes from said dissolving zone, and discharging cleansed high melting point Wax particles from said cleaning zone.

2. In the art of separating waxy materials having diiferent melting points, a counterilow extraction process which comprises dissolving relatively low melting point waxes in a comparatively warm dissolving zone and separating dissolved low melting point wax from solidified wax in a still warmer cleansing zone, said process including the steps of transmitting a stream of relatively warm solvent into said cleansing zone, causing the solvent stream to advance through said cleansing zone and then through said dissolving zone, cooling a liquid solution of said waxy materials to solidify waxes having different melting points, forcibly disintegrating the solidified waxes in the cool liquid solution to r lease trapped solution from the waxes and produce a mixture of minute wax particles having high and low melting points, transmitting the disintegrated wax particles into said warm dissolving zone, causing a stream of the wax particles to advance through said dissolving zone and then through said cleansing zone in contact with but in counterflow relation to said solvent stream, regulating the temperatures to maintain the solvent stream in said dissolving zone at temperatures high enough to selectively dissolve wax fractions having relatively low melting points without dissolving the comparatively high melting point waxes, spreading the stream of disintegrated wax particles in said dissolving and cleansing zones to separate and distribute the minute wax particles in the counterflowing solvent stream, while repeatedly deflecting the distributed wax particles and solvent stream into intersecting paths in said dissolving and cleansing zones, so as to dissolve low melting point waxes in the solvent stream and thereafter scrub dissolved low melting point wax from surfaces of the deflected high melting point wax particles in the warmer cleansing zone, discharging dissolved low melting point waxes from said dissolving zone, and discharging cleansed high melting point wax particles from said cleansing zone.

3. In the art of separating oil and waxes having different melting points, the continuous process which comprises dissolving the oil and waxes in a selective dewaxing solvent, cooling the solution to solidify waxes having comparatively high and low melting points, forcibly breaking the waxes into minute particles in the cool liquid solution, so as to release trapped oil solution from the wax and produce a mixture of minute Wax particles having different melting points, transmitting the mixture of cool liquid solution and broken wax particles into a settling chamber and causing dissolved oil to separate from the Waxes in said settling chamber, discharging the separated dissolved oil from said settling chamber, transmitting the cool wax particles from said settling chamber to a counterflow extracting system having a relatively warm preliminary cleansing zone, a warmer dissolving zone, and a still warmer cleansing zone, introducing a stream of relatively warm solvent into the last mentioned cleansing zone, causing the last mentioned solvent to flow through said last mentioned cleansing zone, then through said dissolving zone and preliminary cleansing zone, while causing wax particles to flow in opposite directions through said zones of different temperatures, maintaining said dissolving zone at temperatures high enough to selectively dissolve low melting point wax particles in the counterflowing solvent without dissolving the high melting point waxes, discharging the solution of dissolved low melting point wax and solvent from said warm dissolving zone and through said preliminary.

cleansing zone, to separate low melting point waxes from the higher melting point waxes, transmitting high melting point wax particles through the counterflowing solvent in said dissolving zone and then through the counterflowing solvent in said still warmer cleansing zone to scrub minor portions of dissolved low melting point waxes from the high melting point wax particles, and discharging the cleansed high melting point wax particles from the last mentioned cleansing zone.

4. In the art of separating waxy materials having different melting points, a counterflow extraction process which comprises dissolving relatively low melting point waxes in a comparatively warm dissolving zone and separating dissolved low melting point wax from solidified wax in a still warmer cleansing zone, said process including the steps of transmitting a stream of relatively warm solvent into the upper portion Of said cleansing zone, causing the solvent stream to descend through said cleansing zone and then through said dissolving zone, cooling a of wax particles in said dissolving and cleansing zones to separate and distribute the wax particles in the counterflowing solvent stream, while repeatedly deflecting the distributed wax particles and "solvent stream into intersecting paths in said dissolving and cleansing zones, so as to dissolve low melting point waxes in the descending solvent stream and thereafter scrub dissolved low melting point wax from surfaces of the deflected high melting point wax particles in the warmer cleansing zone, discharging dissolved low melting point waxes from the lower portion of said dissolving zone, and discharging cleansed high melting point wax particles from the upper portion of said cleansing zone.

5. In the art of separating waxy materials having different melting points, a counterflow extraction process which comprises dissolving relatively low melting point waxes in a comparatively warm dissolving zone and separating dissolved low melting point wax from solidified wax in a still warmer cleansing zone, said process including the steps of transmitting a stream of relatively warm solvent into said cleansing zone, causing the solvent stream to descend through said cleansing zone and then through said dissolving zone, cooling a liquid solution of said waxy materials to solidify waxes having different melting points, forcibly disintegrating the solid ified waxes in the cool liquid solution to release trapped solution from the waxes and produce a mixture of minute wax particles having high and low melting points, transmitting the disintegrated wax particles into said warm dissolving zone, causing a stream of the wax particles to advance through said dissolving zone and then through said cleansing zone in contact with but in counterfiow relation to said solvent stream, regulating the temperatures to maintain the solvent stream in said dissolving zone at temperatures high enough to selectively dissolve wax fractions having relatively low melting points without dissolving the comparatively high melting point waxes, spreading the stream of disintegrated wax particles in said dissolving and cleansing zones to separate and distribute the minute wax particles in the counter-flowing solvent stream, while repeatedly deflecting the distributed wax particles and solvent stream into intersecting paths in said dissolving and cleansing zones, so as to dissolve low melting point waxes in the solvent stream and thereafter scrub dissolved low melting point wax from surfaces of the deflected high melting point wax particles in the Warmer cleansing zone, discharging dissolved low melting point waxes from said dissolving zone, and discharging cleansed high melting point Wax particles from said cleansing zone.

6. In the art of separating oil and waxes having different melting points, the process which comprises dissolving the oil and waxes in a selective dewaxing solvent, cooling the solution to solidify waxes having comparatively high and low melting points, forcibly breaking the waxes into minute particles in the cool liquid solution, so as to release trapped oil solution from the wax and produce a mixture of free wax particles having high and low melting points, transmitting the mixture of cool liquid solution and broken wax particles into a settling chamber and causing dissolved oil to drop by gravity from the waxes in saidsettling chamber, discharging the separated dissolved oil from said settling chamber, transmitting the broken wax particles from the upper portion of said settling chamber to a counterflow extracting system having a relatively warm dissolving zone, and a still warmer cleansing 'z'o'ne,"- introducing relatively warm solvent into said cleansing zone, and also into said dissolving zone, causing the last mentioned solvent to descend through the zones of diiferent temperatures while causing wax particles to rise through said zones, maintaining said warm dissolving zone at temperatures high enough to selectively dissolve rising low melting point waxv particles without dissolving the high melting point waxes, discharging the solution of dissolved low melting point wax and solvent from the lower portion of said dissolving zone to separate low melting point waxes from the higher melting point waxes, transmitting the rising high melting point wax particles through the descending solvent in said dissolving zone and then through the counterflowing solvent in said still warmer cleansing zone to scrub minor portions of dissolved low melting point waxes from the high melting point wax particles, and discharging the cleansed high melting point wax particles from said cleansing zone.

7. In the art of separating waxy materials having different melting points, a counterfiow extraction process which comprises dissolving relatively low melting point waxes in a comparatively warm dissolving zone and separating dissolved low melting point wax from solidified Wax in a still warmer cleansing zone, said process including the steps of causing wax-solvents to de scend in tortuous paths in contact with the top faces of baffles in said dissolving and cleansing zones, cooling a liquid solution of said waxy materials to solidify waxes having different melting points, transmitting the wax particles into said comparatively warm dissolving zone, causing a stream of the wax particles to rise in tortuous paths through said dissolving zone and then through said still warmer cleansing zone in contact with but in counterflow relation to the solvents, while forming upwardly inclined layers of said rising wax particles on inclined bottom faces of said baflles, deflecting said upwardly inclined layers of rising wax particles into the paths of said descending Wax solvents, thereby causing the rising Wax particles to repeatedly intersect paths of said solvents in said dissolving and cleansing zones, so as to dissolve low melting point waxes in the dissolving zone, and thereafter scrub dissolved low melting point waxes from surfaces of the deflected high melting point wax particles in the warmer dissolving zone, discharging dissolved low melting point waxes from said dissolving zone, and discharging cleansed high melting point wax particles from said cleansing zone.

8. In the art of separating waxy materials having difierent melting points, a counterflow extraction process which comprises dissolving relatively low melting point waxes in a comparatively warm dissolving zone and separating dissolved low melting point wax from solidified wax in a still warmer cleansing zone, said process including the steps of causing wax-solvents to descend in tortuous paths in contact with the top faces of bame in said dissolving and cleansing zones, cooling a liquid solution of said waxy materials to solidify waxes having different melting points, transmitting the wax particles into said comparatively warm dissolving zone, causing a stream of the wax particles to rise in tortuous paths through said dissolving zone and then, through said still warmer cleansing zone in contact with but in counterflow relation to the solvents, .while forming upwardly inclined layers of said rising wax particles on inclined bottom faces of said baflles, deflecting said upwardly inclined layers of rising wax particles into the paths of said descending wax solvents, thereby causing the rising wax particles to repeatedly intersect paths of said solvents in said dissolving and cleansing zones, so as to dissolve low melting point waxes in the dissolving zone, and thereafter scrub dissolved low melting point waxes from surfaces of the deflected high melting point wax particles in the warmer dissolving zone, mechanically removing extended portions of wax deposits on said inclined bottom faces to permit continuous flow of wax and solvents through said zones, discharging dissolved low melting point waxes from said dissolving zone, and discharging cleansed high melting point wax particles from said cleansing zone.

9. A process as in claim 4 wherein the relatively warm descending solvent includes methylene dichloride.

10. A process as in claim 4 wherein the relatively warm descending solvent includes methylene dichloride and dichlorethyl ether.

11. A process as in claim 4 wherein the relatively warm descending solvent includes methylene dichloride and sulfur dioxide.

EDDIE M. DONS. OSWALD G. MAURO. 

